libblkid: don't return empty LABELs

Signed-off-by: Karel Zak <kzak@redhat.com>

3 files changed, 25 insertions, 1 deletions

diff --git a/shlibs/blkid/src/blkidP.h b/shlibs/blkid/src/blkidP.h
index 6e9c21e8e..90900e27e 100644
--- a/shlibs/blkid/src/blkidP.h
+++ b/shlibs/blkid/src/blkidP.h
@@ -379,6 +379,7 @@ extern void blkid_probe_chain_reset_vals(blkid_probe pr, struct blkid_chain *chn
 extern int blkid_probe_chain_copy_vals(blkid_probe pr, struct blkid_chain *chn,
 			                struct blkid_prval *vals, int nvals);
 extern struct blkid_prval *blkid_probe_assign_value(blkid_probe pr, const char *name);
+extern int blkid_probe_reset_last_value(blkid_probe pr);
 extern void blkid_probe_append_vals(blkid_probe pr, struct blkid_prval *vals, int nvals);
 
 extern struct blkid_chain *blkid_probe_get_chain(blkid_probe pr);
diff --git a/shlibs/blkid/src/probe.c b/shlibs/blkid/src/probe.c
index f8610cb61..0324351ab 100644
--- a/shlibs/blkid/src/probe.c
+++ b/shlibs/blkid/src/probe.c
@@ -848,6 +848,25 @@ struct blkid_prval *blkid_probe_assign_value(
 	return v;
 }
 
+int blkid_probe_reset_last_value(blkid_probe pr)
+{
+	struct blkid_prval *v;
+
+	if (pr == NULL || pr->nvals == 0)
+		return -1;
+
+	v = &pr->vals[pr->nvals - 1];
+
+	DBG(DEBUG_LOWPROBE,
+		printf("un-assigning %s [%s]\n", v->name, v->chain->driver->name));
+
+	memset(v, 0, sizeof(struct blkid_prval));
+	pr->nvals--;
+
+	return 0;
+
+}
+
 int blkid_probe_set_value(blkid_probe pr, const char *name,
 		unsigned char *data, size_t len)
 {
@@ -878,7 +897,7 @@ int blkid_probe_vsprintf_value(blkid_probe pr, const char *name,
 	len = vsnprintf((char *) v->data, sizeof(v->data), fmt, ap);
 
 	if (len <= 0) {
-		pr->nvals--; /* reset the latest assigned value */
+		blkid_probe_reset_last_value(pr);
 		return -1;
 	}
 	v->len = len + 1;
diff --git a/shlibs/blkid/src/superblocks/superblocks.c b/shlibs/blkid/src/superblocks/superblocks.c
index 6fb2be3a7..f625f271b 100644
--- a/shlibs/blkid/src/superblocks/superblocks.c
+++ b/shlibs/blkid/src/superblocks/superblocks.c
@@ -501,6 +501,8 @@ int blkid_probe_set_label(blkid_probe pr, unsigned char *label, size_t len)
 	v->data[len] = '\0';
 
 	v->len = blkid_rtrim_whitespace(v->data) + 1;
+	if (v->len == 1)
+		blkid_probe_reset_last_value(pr);
 	return 0;
 }
 
@@ -521,6 +523,8 @@ int blkid_probe_set_utf8label(blkid_probe pr, unsigned char *label,
 
 	blkid_encode_to_utf8(enc, v->data, sizeof(v->data), label, len);
 	v->len = blkid_rtrim_whitespace(v->data) + 1;
+	if (v->len == 1)
+		blkid_probe_reset_last_value(pr);
 	return 0;
 }